For many years, it has been common to display advertising materials on buses, taxis, cars or other motor vehicles. The advertisement material is usually placed on the rear or sides of the vehicle. The advertising material is slid into a holder which is fixed in place on the vehicle and visible to other vehicles or passersby.
In U.S. Pat. No. 2,812,605, issued Nov. 12, 1957, a sign is held in place by a body panel which is directly attached to a motor vehicle. The panel has a hinged frame which permits outward swinging movement and a locking lever which secures the frame to the vehicle. Brackets are provided to secure the panel to the trunk of the vehicle.
Some patents disclose advertising materials which are unwound from a roll. For example, U.S. Pat. No. 3,430,374, issued Nov. 15, 1966, discloses a sign displayed on a flexible sheet stored in a rolled condition under spring tension in the interior of the trunk of the vehicle. When the trunk is opened, the sheet is extended so as to secure the sheet to the lower portion of the trunk. In U.S. Pat. No. 505,682, issued Sept. 26, 1893, a roll containing various advertisements is connected to the wheels of a vehicle so as to change the display as the vehicle travels.
U.S. Pat. No. 3,594,934, issued July 27, 1971, discloses a display connected to the rear of a vehicle wherein the sign is contained on a flexible sheet reinforced by rod-like elements. Elastic straps are attached to the ends of the rod-like elements and the straps stretch around the truck or any suitable protuberance at the rear of the vehicle to secure the sign to the vehicle.